The air conditioner blows the nose, consider two possibilities: First, the cold air in the air conditioner stimulates the mucous membrane of the nasal cavity, resulting in a transient congestion and edema of the mucous membrane of the nasal cavity, resulting in the narrowing of the nasal cavity lumen, resulting in nasal congestion, the nose is not ventilated. This situation is generally self-limiting, when people enter the higher temperature environment, nasal congestion symptoms will be naturally relieved. Second, consider whether there is allergic rhinitis. Because the cold air blown out of the air conditioner or the presence of the corresponding allergens in the air conditioning filter is an obvious trigger for allergic rhinitis. When allergic rhinitis attacks, nasal secretions increase, while inflammatory exudation, congestion and edema changes in the nasal cavity, resulting in the symptoms of a blocked nose. In this case, in addition to getting out of this air-conditioned environment, antihistamines can be given to relieve the symptoms of nasal congestion. The usual medications include cetirizine hydrochloride, loratadine, etc.